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Dietary Supplements

  • Too Much of a Good Thing?

  • As a young dietitian in 1980, it was rare for anyone to ask my advice regarding dietary supplements. My, how times have changed. And no wonder! Almost every grocery store and retail pharmacy today dedicates whole sections of shelf space to displays of supplements.

    With so much retail and advertisement exposure, along with their seductive claims for re-invigorating lives, dietary supplements have captured America’s imagination. But, do they deliver on their promises? Are they worth the cost?

    The 1994 Dietary Supplement Health and Education Act was intended to regulate the growing industry and to make the use of supplements safer. The law holds manufacturers responsible for their claims, though they do not have to provide evidence that the supplement is safe in advance of going to market.

    The law also defined the term “dietary supplement” to be: a product (other than tobacco) that:

    • Is intended to supplement the diet.
    • Contains one or more dietary ingredients (including vitamins, minerals, herbs or other botanicals, amino acids, and other substances) or their constituents.
    • Is intended to be taken by mouth as a pill, capsule, tablet, or liquid.
    • Is labeled on the front panel as being a dietary supplement.

    Taken as a whole, dietary supplements are confusing, with the potential to provide both health gains and risks. But, let’s not throw away the baby with the bathwater.

    We know that some supplements are valuable as long as the concept of “supplement” is applied – something that is “added to” the basic diet. A supplement is taken when the basic diet cannot meet the recommended amount of a food–derived compound or nutrient. Keep in mind that too much of a good thing can become a bad thing.

    Impulse buying is not advised when it comes to dietary supplements. Do your homework; use a reputable source to research the supplement you are thinking of using. The best sources are the UC Berkeley publication: Wellness Guide To Dietary Supplements and the website of the National Institutes of Health Office of Dietary Supplements.

    In the case of supplements, the amount of a nutrient or compound the whole diet provides must also be counted. Combining food intake with dietary supplement intake might provide an excess of a nutrient, which can result in a complication.

    Let’s use Vitamin D as an example. Vitamin D is required for bone health, and there is now some evidence that it might help protect us against high blood pressure and diabetes.

    Our bodies manufacture Vitamin D when we have adequate sunlight exposure. In addition, it is added to (fortified) dairy products in the U.S.A. The current recommended intake of dietary Vitamin D is 400 IU (international units) per day, assuming sunlight exposure will result in our ability to meet the rest of our Vitamin D requirement. But, newer research has suggested that 800 IU may be required to prevent bone fractures and protect against some chronic diseases, especially in the elderly and for people with dark skin.

    And while Vitamin D’s importance to health is being more widely recognized, sunscreen use and protection strengths have dramatically increased in order to prevent skin cancers and damage, and this limits the amount the average person receives from exposure to sunlight. The bottom line: Vitamin D is a popular supplement today.

    But, if the dietary intake recommendation for Vitamin D is 400 IU, or 800 IU, or even 1,000 IU as recommended by some, consider that this is the recommendation for all intake, not just the supplement dose. One glass of milk (fortified with Vitamin D) provides about 100 IU of Vitamin D. One dose of a calcium supplement that also contains Vitamin D (a common combination) provides 200 IU of Vitamin D, and taking this twice a day will provide a total of 400 IU of Vitamin D. Then there is oily fish (salmon, for example), which provides 360 IU of Vitamin D per 3.5- ounce serving.

    Well, you get the idea. A person who does not go outdoors except with strong sunscreen; who does not tolerate milk; who is allergic to fish and who prefers to take a calcium supplement alone, would probably benefit from a Vitamin D supplement of 400 IU to 800 IU.

    On the other hand, a person who regularly eats salmon, consumes two or more cups of milk daily and who takes calcium with Vitamin D will easily get more than 1,000 IU of Vitamin D per day, without a separate supplement. And, if a supplement were to be added to the Vitamin D-rich diet described above, harmful effects could result, including the possibility of kidney stones, heart arrhythmia, weight loss and mental confusion. Children and the elderly are most at risk

    So, what are some other health-enhancing dietary supplements in the context of a diet that cannot provide the recommended amount? One we have already mentioned is supplemental calcium. For every age, calcium intake adequacy is essential to good health, but this is especially true for adolescents and older adults who have higher calcium requirements: 1,300 mg/day for adolescents, 1,200 mg/day for older adults vs. 1,000 mg/day for younger adults.

    One cup of milk or yogurt provides about 300 mg of calcium; three to four servings a day of these dairy foods will meet the needs of most teens and adults. But many people do not eat dairy foods, and for them, calcium supplements are important to maintain good bone health and help protect against high blood pressure.

    Finally, Omega-3 fatty acids are supplemented by many people in the form of flaxseed (eicosapentaenoic acid or EPA) or fish oil (docosahexaenoic acid or DHA). Typical western diets are notoriously low in Omega-3 fatty acids, which help maintain a healthy balance of the immune system and are important for brain development and function.

    But again, Omega-3 fatty acids are found naturally in some foods that can be added to the diet without the expense of another supplement. DHA is very rich in some fish, especially wild salmon. And EPA is found in canola oil and soy oil.

    Because Omega-3 fatty acids reduce clotting function of the blood, people who take a blood thinning medication should always check with their doctor before adding this dietary supplement.

    No matter what dietary supplement you may be interested in using, remember this advice from the National Institutes of Health Office of Dietary Supplements: supplements are not intended to treat, diagnose, mitigate, prevent, or cure disease, and in some cases, may have unwanted effects.

    Do not self-diagnose any health condition. Rather, work with your healthcare provider to determine how best to achieve optimal health. and always check with your provider before taking a supplement, especially when combining or substituting it with other foods or medicines.

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